Nerve attack: Sergei Skripal pictured at his trial in Moscow. Photo: APTables and chairs remain unused inside the closed pub which Sergei Skripal and his daughter Yulia visited before they were found poisoned. REUTERSA police car being taken away by military personnel in Salisbury, as police and members of the armed forces probe the suspected nerve agent attack. Photo: Andrew Matthews/PA WireForensic officers in gas masks at the cemetery where former Russian double agent Sergei Skripal’s wife and son were laid to rest. Photo: PA WireOfficials take off their protective suits near the bench where Sergei Skripal and his daughter Yulia were found in Salisbury. Photo: ReutersMembers of the emergency services put a tent over the bench where Sergei Skripal and his daughter were found

High quality CCTV footage of Sergei Skripal and his daughter in the moments before they collapsed has been passed to investigators probing the attack of a Russian former double agent.

The images are understood to be clear enough to see people's faces or read a car number plate.

There were fears the city's £400,000 CCTV system may not have been working after it was besieged by technical problems.

But Matthew Dean, leader of Salisbury City Council, said the issues had been resolved around a month ago.

Crucially, the coverage includes The Maltings area, where Mr Skripal, 66, and Yulia, 33, were found collapsed on a bench eight days ago.

"The CCTV system was fully functional and a great deal of footage has been shared with the enquiry," he said.

Tables and chairs remain unused inside the closed pub which Sergei Skripal and his daughter Yulia visited before they were found poisoned. REUTERS

"I can confirm some very high quality footage was shared on the Monday with the enquiry."

The images showing the victims in the hours and minutes before their collapse could be invaluable to investigators, who continue to scour the city for clues.

A police car being taken away by military personnel in Salisbury, as police and members of the armed forces probe the suspected nerve agent attack. Photo: Andrew Matthews/PA Wire

Police cordons remain in place at various locations in Salisbury, while the military have been working with counter-terror police to remove potentially contaminated vehicles and other items.

"People are used to seeing the military around," said Mr Dean.

Forensic officers in gas masks at the cemetery where former Russian double agent Sergei Skripal’s wife and son were laid to rest. Photo: PA Wire

"I think we are very fortunate as we have a military presence anyway.

"It is the home of the British Army and Porton Down, the chemical weapons research facility, is located just outside of the city."

The Conservative politician also defended fresh health advice issued a week after the attack when it emerged traces of a nerve agent had been found at The Mill pub and the nearby Zizzi restaurant.

"If there is anger I haven't discerned it. People accept that this incident is unprecedented in the British Isles and it took Public Health England some days of investigative science to find out even what the cause of injury was to Mr Skripal and his daughter.

"So the advice of yesterday was following the last few days of scientific analysis."